The parent application discloses method and apparatus to monitor behavioral correlates of brain function. The rate of speech pausing or hiatus rates of other neuromotor functions correlates negatively to the efficiency of dominant, usually left brain hemisphere function, such as in Broca's Aphasia and Parkinson's Disease; longer, less recurrent pauses or hiatuses are indicators of efficiency of the right brain hemisphere, i.e., echo-time (MS Gazzaniga, The Bisected Brain, New York Academic Press, 1970).
Coordinated hemispheric functioning to perform complex tasks, as described by P. Wolff on Aug. 6, 1982, cited in the parent patent, is mediated by interhemispheric transmission time in the order of 2.5 to 20 msec. Longer times are required to process visual stimuli by the occipital cortex compared with the processing of non-visual stimuli by other regions of the cerebral cortex. A complex activity such as focal visual attention for red-green discrimination, which necessarily is mediated by the opponent cells in the visual cortex, requires 16.6 msec processing time (Science 228: 1217-1219, 1985).
An increase in hiatus time from lower to higher fluency, utilizing software disclosed in the parent patent expanded to the fourth decimal place, is a measure of a shift from left to right hemispheric brain activity, hence, an objective indicator of interhemispheric transmission time.
U.S. Pat. No. 3,983,535 discloses that muscle contractions during highly practiced motions such as signature writing are controlled without sensory feedback to an accuracy of about 5 msec. Hand-brain-hand propagation time restricts feedback effects to be greater than 100 msec. Such longer time intervals typically occur during a pause in writing between the first and last name. U.S. Pat. No. 3,983,535 makes no provision for monitoring these pauses to identify writing style that is consistent over time and that can enhance accuracy in signature verification. Similarly, this method and apparatus may be utilized in testing and training pilot trainees on a flight simulator where neuromotor responses are likewise monitored in reaction to sensory inputs to the two hemispheres. The right eye only sees liquid crystal digital displays of helicopter functions which are processed by the mathematically oriented left hemisphere while the left eye perceives real word scenes on the simulator which are processed primarily by the spatially talented right hemisphere.
These neuromotor activities are subserved by neural motor networks in the left hemisphere and specific areas in the right hemisphere that maintain vigilance (Arch Neurol 41: 843-852, 1984). Motoric activity is subserved by dopamine (Science 229: 62-65, 1985).
By using the greater than 100 msec threshold, this invention discloses newer data and methods and apparatus for monitoring motor cortex activity on the left rather than just speech at the one second plus threshold for Broca's Area as disclosed in the prior patents and application.